Refactoring: hide internal fields of ring buffer context
[lttng-ust.git] / libringbuffer / ring_buffer_frontend.c
index 9b16685251ee1e1d8da49801c1f11ca61ec2060a..8112ced4719f118c256ab07c29e4b3780351ebcd 100644 (file)
@@ -1,23 +1,8 @@
 /*
- * ring_buffer_frontend.c
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
  * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- *
  * Ring buffer wait-free buffer synchronization. Producer-consumer and flight
  * recorder (overwrite) modes. See thesis:
  *
@@ -51,7 +36,6 @@
  *   - put_subbuf
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <signal.h>
 #include <time.h>
 #include <stdbool.h>
+#include <stdint.h>
 #include <urcu/compiler.h>
 #include <urcu/ref.h>
 #include <urcu/tls-compat.h>
 #include <poll.h>
-#include <helper.h>
+#include <ust-helper.h>
+
+#include <lttng/ust-utils.h>
+#include <lttng/ringbuffer-context.h>
 
 #include "smp.h"
-#include <lttng/ringbuffer-config.h>
+#include "ringbuffer-config.h"
 #include "vatomic.h"
 #include "backend.h"
 #include "frontend.h"
@@ -127,7 +115,7 @@ DEFINE_URCU_TLS(unsigned int, lib_ring_buffer_nesting);
 static pthread_mutex_t wakeup_fd_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 static
-void lib_ring_buffer_print_errors(struct channel *chan,
+void lib_ring_buffer_print_errors(struct lttng_ust_lib_ring_buffer_channel *chan,
                                struct lttng_ust_lib_ring_buffer *buf, int cpu,
                                struct lttng_ust_shm_handle *handle);
 
@@ -151,12 +139,19 @@ static struct timer_signal_data timer_signal = {
        .lock = PTHREAD_MUTEX_INITIALIZER,
 };
 
-int lttng_ust_blocking_retry_timeout =
-               CONFIG_LTTNG_UST_DEFAULT_BLOCKING_RETRY_TIMEOUT_MS;
+static bool lttng_ust_allow_blocking;
 
-void lttng_ust_ringbuffer_set_retry_timeout(int timeout)
+void lttng_ust_ringbuffer_set_allow_blocking(void)
 {
-       lttng_ust_blocking_retry_timeout = timeout;
+       lttng_ust_allow_blocking = true;
+}
+
+/* Get blocking timeout, in ms */
+static int lttng_ust_ringbuffer_get_timeout(struct lttng_ust_lib_ring_buffer_channel *chan)
+{
+       if (!lttng_ust_allow_blocking)
+               return 0;
+       return chan->u.s.blocking_timeout_ms;
 }
 
 /**
@@ -171,7 +166,7 @@ void lttng_ust_ringbuffer_set_retry_timeout(int timeout)
 void lib_ring_buffer_reset(struct lttng_ust_lib_ring_buffer *buf,
                           struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
        unsigned int i;
 
@@ -187,6 +182,7 @@ void lib_ring_buffer_reset(struct lttng_ust_lib_ring_buffer *buf,
        for (i = 0; i < chan->backend.num_subbuf; i++) {
                struct commit_counters_hot *cc_hot;
                struct commit_counters_cold *cc_cold;
+               uint64_t *ts_end;
 
                cc_hot = shmp_index(handle, buf->commit_hot, i);
                if (!cc_hot)
@@ -194,9 +190,13 @@ void lib_ring_buffer_reset(struct lttng_ust_lib_ring_buffer *buf,
                cc_cold = shmp_index(handle, buf->commit_cold, i);
                if (!cc_cold)
                        return;
+               ts_end = shmp_index(handle, buf->ts_end, i);
+               if (!ts_end)
+                       return;
                v_set(config, &cc_hot->cc, 0);
                v_set(config, &cc_hot->seq, 0);
                v_set(config, &cc_cold->cc_sb, 0);
+               *ts_end = 0;
        }
        uatomic_set(&buf->consumed, 0);
        uatomic_set(&buf->record_disabled, 0);
@@ -220,7 +220,7 @@ void lib_ring_buffer_reset(struct lttng_ust_lib_ring_buffer *buf,
  * be using the iterator concurrently with reset. The previous current iterator
  * record is reset.
  */
-void channel_reset(struct channel *chan)
+void channel_reset(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        /*
         * Reset iterators first. Will put the subbuffer if held for reading.
@@ -331,11 +331,12 @@ int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
                           struct shm_object *shmobj)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config;
-       struct channel *chan = caa_container_of(chanb, struct channel, backend);
+       struct lttng_ust_lib_ring_buffer_channel *chan = caa_container_of(chanb,
+                       struct lttng_ust_lib_ring_buffer_channel, backend);
        struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb;
-       struct channel *shmp_chan;
+       struct lttng_ust_lib_ring_buffer_channel *shmp_chan;
        struct commit_counters_hot *cc_hot;
-       void *priv = channel_get_private(chan);
+       void *priv = channel_get_private_config(chan);
        size_t subbuf_header_size;
        uint64_t tsc;
        int ret;
@@ -361,6 +362,16 @@ int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
                goto free_commit;
        }
 
+       align_shm(shmobj, __alignof__(uint64_t));
+       set_shmp(buf->ts_end,
+                zalloc_shm(shmobj,
+                       sizeof(uint64_t) * chan->backend.num_subbuf));
+       if (!shmp(handle, buf->ts_end)) {
+               ret = -ENOMEM;
+               goto free_commit_cold;
+       }
+
+
        ret = lib_ring_buffer_backend_create(&buf->backend, &chan->backend,
                        cpu, handle, shmobj);
        if (ret) {
@@ -407,6 +418,8 @@ int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
 
        /* Error handling */
 free_init:
+       /* ts_end will be freed by shm teardown */
+free_commit_cold:
        /* commit_cold will be freed by shm teardown */
 free_commit:
        /* commit_hot will be freed by shm teardown */
@@ -419,7 +432,7 @@ void lib_ring_buffer_channel_switch_timer(int sig, siginfo_t *si, void *uc)
 {
        const struct lttng_ust_lib_ring_buffer_config *config;
        struct lttng_ust_shm_handle *handle;
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        int cpu;
 
        assert(CMM_LOAD_SHARED(timer_signal.tid) == pthread_self());
@@ -463,7 +476,7 @@ end:
 static
 int lib_ring_buffer_poll_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
                                 struct lttng_ust_lib_ring_buffer *buf,
-                                struct channel *chan,
+                                struct lttng_ust_lib_ring_buffer_channel *chan,
                                 struct lttng_ust_shm_handle *handle)
 {
        unsigned long consumed_old, consumed_idx, commit_count, write_offset;
@@ -572,7 +585,7 @@ void lib_ring_buffer_wakeup(struct lttng_ust_lib_ring_buffer *buf,
 }
 
 static
-void lib_ring_buffer_channel_do_read(struct channel *chan)
+void lib_ring_buffer_channel_do_read(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        const struct lttng_ust_lib_ring_buffer_config *config;
        struct lttng_ust_shm_handle *handle;
@@ -617,7 +630,7 @@ end:
 static
 void lib_ring_buffer_channel_read_timer(int sig, siginfo_t *si, void *uc)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
 
        assert(CMM_LOAD_SHARED(timer_signal.tid) == pthread_self());
        chan = si->si_value.sival_ptr;
@@ -767,7 +780,7 @@ void lib_ring_buffer_wait_signal_thread_qs(unsigned int signr)
 }
 
 static
-void lib_ring_buffer_channel_switch_timer_start(struct channel *chan)
+void lib_ring_buffer_channel_switch_timer_start(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        struct sigevent sev;
        struct itimerspec its;
@@ -780,6 +793,7 @@ void lib_ring_buffer_channel_switch_timer_start(struct channel *chan)
 
        lib_ring_buffer_setup_timer_thread();
 
+       memset(&sev, 0, sizeof(sev));
        sev.sigev_notify = SIGEV_SIGNAL;
        sev.sigev_signo = LTTNG_UST_RB_SIG_FLUSH;
        sev.sigev_value.sival_ptr = chan;
@@ -800,7 +814,7 @@ void lib_ring_buffer_channel_switch_timer_start(struct channel *chan)
 }
 
 static
-void lib_ring_buffer_channel_switch_timer_stop(struct channel *chan)
+void lib_ring_buffer_channel_switch_timer_stop(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        int ret;
 
@@ -819,7 +833,7 @@ void lib_ring_buffer_channel_switch_timer_stop(struct channel *chan)
 }
 
 static
-void lib_ring_buffer_channel_read_timer_start(struct channel *chan)
+void lib_ring_buffer_channel_read_timer_start(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        struct sigevent sev;
@@ -854,7 +868,7 @@ void lib_ring_buffer_channel_read_timer_start(struct channel *chan)
 }
 
 static
-void lib_ring_buffer_channel_read_timer_stop(struct channel *chan)
+void lib_ring_buffer_channel_read_timer_stop(struct lttng_ust_lib_ring_buffer_channel *chan)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        int ret;
@@ -880,14 +894,14 @@ void lib_ring_buffer_channel_read_timer_stop(struct channel *chan)
        chan->read_timer_enabled = 0;
 }
 
-static void channel_unregister_notifiers(struct channel *chan,
+static void channel_unregister_notifiers(struct lttng_ust_lib_ring_buffer_channel *chan,
                           struct lttng_ust_shm_handle *handle)
 {
        lib_ring_buffer_channel_switch_timer_stop(chan);
        lib_ring_buffer_channel_read_timer_stop(chan);
 }
 
-static void channel_print_errors(struct channel *chan,
+static void channel_print_errors(struct lttng_ust_lib_ring_buffer_channel *chan,
                struct lttng_ust_shm_handle *handle)
 {
        const struct lttng_ust_lib_ring_buffer_config *config =
@@ -910,7 +924,7 @@ static void channel_print_errors(struct channel *chan,
        }
 }
 
-static void channel_free(struct channel *chan,
+static void channel_free(struct lttng_ust_lib_ring_buffer_channel *chan,
                struct lttng_ust_shm_handle *handle,
                int consumer)
 {
@@ -924,9 +938,10 @@ static void channel_free(struct channel *chan,
  * channel_create - Create channel.
  * @config: ring buffer instance configuration
  * @name: name of the channel
- * @priv_data: ring buffer client private data area pointer (output)
- * @priv_data_size: length, in bytes, of the private data area.
- * @priv_data_init: initialization data for private data.
+ * @priv_data_align: alignment, in bytes, of the private data area. (config)
+ * @priv_data_size: length, in bytes, of the private data area. (config)
+ * @priv_data_init: initialization data for private data. (config)
+ * @priv: local private data (memory owner by caller)
  * @buf_addr: pointer the the beginning of the preallocated buffer contiguous
  *            address mapping. It is used only by RING_BUFFER_STATIC
  *            configuration. It can be set to NULL for other backends.
@@ -944,21 +959,23 @@ static void channel_free(struct channel *chan,
  */
 struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buffer_config *config,
                   const char *name,
-                  void **priv_data,
                   size_t priv_data_align,
                   size_t priv_data_size,
                   void *priv_data_init,
+                  void *priv,
                   void *buf_addr, size_t subbuf_size,
                   size_t num_subbuf, unsigned int switch_timer_interval,
                   unsigned int read_timer_interval,
-                  const int *stream_fds, int nr_stream_fds)
+                  const int *stream_fds, int nr_stream_fds,
+                  int64_t blocking_timeout)
 {
        int ret;
        size_t shmsize, chansize;
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        struct lttng_ust_shm_handle *handle;
        struct shm_object *shmobj;
        unsigned int nr_streams;
+       int64_t blocking_timeout_ms;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
                nr_streams = num_possible_cpus();
@@ -968,6 +985,19 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
        if (nr_stream_fds != nr_streams)
                return NULL;
 
+       if (blocking_timeout < -1) {
+               return NULL;
+       }
+       /* usec to msec */
+       if (blocking_timeout == -1) {
+               blocking_timeout_ms = -1;
+       } else {
+               blocking_timeout_ms = blocking_timeout / 1000;
+               if (blocking_timeout_ms != (int32_t) blocking_timeout_ms) {
+                       return NULL;
+               }
+       }
+
        if (lib_ring_buffer_check_config(config, switch_timer_interval,
                                         read_timer_interval))
                return NULL;
@@ -982,20 +1012,20 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
                goto error_table_alloc;
 
        /* Calculate the shm allocation layout */
-       shmsize = sizeof(struct channel);
-       shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_shmp));
+       shmsize = sizeof(struct lttng_ust_lib_ring_buffer_channel);
+       shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_shmp));
        shmsize += sizeof(struct lttng_ust_lib_ring_buffer_shmp) * nr_streams;
        chansize = shmsize;
        if (priv_data_align)
-               shmsize += offset_align(shmsize, priv_data_align);
+               shmsize += lttng_ust_offset_align(shmsize, priv_data_align);
        shmsize += priv_data_size;
 
        /* Allocate normal memory for channel (not shared) */
        shmobj = shm_object_table_alloc(handle->table, shmsize, SHM_OBJECT_MEM,
-                       -1);
+                       -1, -1);
        if (!shmobj)
                goto error_append;
-       /* struct channel is at object 0, offset 0 (hardcoded) */
+       /* struct lttng_ust_lib_ring_buffer_channel is at object 0, offset 0 (hardcoded) */
        set_shmp(handle->chan, zalloc_shm(shmobj, chansize));
        assert(handle->chan._ref.index == 0);
        assert(handle->chan._ref.offset == 0);
@@ -1006,6 +1036,8 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
 
        /* space for private data */
        if (priv_data_size) {
+               void *priv_config;
+
                DECLARE_SHMP(void, priv_data_alloc);
 
                align_shm(shmobj, priv_data_align);
@@ -1013,14 +1045,16 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
                set_shmp(priv_data_alloc, zalloc_shm(shmobj, priv_data_size));
                if (!shmp(handle, priv_data_alloc))
                        goto error_append;
-               *priv_data = channel_get_private(chan);
-               memcpy(*priv_data, priv_data_init, priv_data_size);
+               priv_config = channel_get_private_config(chan);
+               memcpy(priv_config, priv_data_init, priv_data_size);
        } else {
                chan->priv_data_offset = -1;
-               if (priv_data)
-                       *priv_data = NULL;
        }
 
+       chan->u.s.blocking_timeout_ms = (int32_t) blocking_timeout_ms;
+
+       channel_set_private(chan, priv);
+
        ret = channel_backend_init(&chan->backend, name, config,
                                   subbuf_size, num_subbuf, handle,
                                   stream_fds);
@@ -1065,7 +1099,7 @@ struct lttng_ust_shm_handle *channel_handle_create(void *data,
                        memory_map_size, wakeup_fd);
        if (!object)
                goto error_table_object;
-       /* struct channel is at object 0, offset 0 (hardcoded) */
+       /* struct lttng_ust_lib_ring_buffer_channel is at object 0, offset 0 (hardcoded) */
        handle->chan._ref.index = 0;
        handle->chan._ref.offset = 0;
        return handle;
@@ -1099,7 +1133,7 @@ unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle)
 }
 
 static
-void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle,
+void channel_release(struct lttng_ust_lib_ring_buffer_channel *chan, struct lttng_ust_shm_handle *handle,
                int consumer)
 {
        channel_free(chan, handle, consumer);
@@ -1113,9 +1147,9 @@ void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle,
  * Call "destroy" callback, finalize channels, decrement the channel
  * reference count. Note that when readers have completed data
  * consumption of finalized channels, get_subbuf() will return -ENODATA.
- * They should release their handle at that point. 
+ * They should release their handle at that point.
  */
-void channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
+void channel_destroy(struct lttng_ust_lib_ring_buffer_channel *chan, struct lttng_ust_shm_handle *handle,
                int consumer)
 {
        if (consumer) {
@@ -1140,7 +1174,7 @@ void channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
 
 struct lttng_ust_lib_ring_buffer *channel_get_ring_buffer(
                                        const struct lttng_ust_lib_ring_buffer_config *config,
-                                       struct channel *chan, int cpu,
+                                       struct lttng_ust_lib_ring_buffer_channel *chan, int cpu,
                                        struct lttng_ust_shm_handle *handle,
                                        int *shm_fd, int *wait_fd,
                                        int *wakeup_fd,
@@ -1164,7 +1198,7 @@ struct lttng_ust_lib_ring_buffer *channel_get_ring_buffer(
 }
 
 int ring_buffer_channel_close_wait_fd(const struct lttng_ust_lib_ring_buffer_config *config,
-                       struct channel *chan,
+                       struct lttng_ust_lib_ring_buffer_channel *chan,
                        struct lttng_ust_shm_handle *handle)
 {
        struct shm_ref *ref;
@@ -1174,7 +1208,7 @@ int ring_buffer_channel_close_wait_fd(const struct lttng_ust_lib_ring_buffer_con
 }
 
 int ring_buffer_channel_close_wakeup_fd(const struct lttng_ust_lib_ring_buffer_config *config,
-                       struct channel *chan,
+                       struct lttng_ust_lib_ring_buffer_channel *chan,
                        struct lttng_ust_shm_handle *handle)
 {
        struct shm_ref *ref;
@@ -1184,7 +1218,7 @@ int ring_buffer_channel_close_wakeup_fd(const struct lttng_ust_lib_ring_buffer_c
 }
 
 int ring_buffer_stream_close_wait_fd(const struct lttng_ust_lib_ring_buffer_config *config,
-                       struct channel *chan,
+                       struct lttng_ust_lib_ring_buffer_channel *chan,
                        struct lttng_ust_shm_handle *handle,
                        int cpu)
 {
@@ -1201,7 +1235,7 @@ int ring_buffer_stream_close_wait_fd(const struct lttng_ust_lib_ring_buffer_conf
 }
 
 int ring_buffer_stream_close_wakeup_fd(const struct lttng_ust_lib_ring_buffer_config *config,
-                       struct channel *chan,
+                       struct lttng_ust_lib_ring_buffer_channel *chan,
                        struct lttng_ust_shm_handle *handle,
                        int cpu)
 {
@@ -1233,7 +1267,7 @@ int lib_ring_buffer_open_read(struct lttng_ust_lib_ring_buffer *buf,
 void lib_ring_buffer_release_read(struct lttng_ust_lib_ring_buffer *buf,
                                  struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan = shmp(handle, buf->backend.chan);
+       struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 
        if (!chan)
                return;
@@ -1256,7 +1290,7 @@ int lib_ring_buffer_snapshot(struct lttng_ust_lib_ring_buffer *buf,
                             unsigned long *consumed, unsigned long *produced,
                             struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
        unsigned long consumed_cur, write_offset;
        int finalized;
@@ -1321,9 +1355,8 @@ int lib_ring_buffer_snapshot_sample_positions(
                             unsigned long *consumed, unsigned long *produced,
                             struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
-       unsigned long consumed_cur, write_offset;
 
        chan = shmp(handle, buf->backend.chan);
        if (!chan)
@@ -1353,7 +1386,7 @@ void lib_ring_buffer_move_consumer(struct lttng_ust_lib_ring_buffer *buf,
                                   struct lttng_ust_shm_handle *handle)
 {
        struct lttng_ust_lib_ring_buffer_backend *bufb = &buf->backend;
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        unsigned long consumed;
 
        chan = shmp(handle, bufb->chan);
@@ -1384,7 +1417,7 @@ int lib_ring_buffer_get_subbuf(struct lttng_ust_lib_ring_buffer *buf,
                               unsigned long consumed,
                               struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
        unsigned long consumed_cur, consumed_idx, commit_count, write_offset;
        int ret, finalized, nr_retry = LTTNG_UST_RING_BUFFER_GET_RETRY;
@@ -1548,7 +1581,7 @@ void lib_ring_buffer_put_subbuf(struct lttng_ust_lib_ring_buffer *buf,
                                struct lttng_ust_shm_handle *handle)
 {
        struct lttng_ust_lib_ring_buffer_backend *bufb = &buf->backend;
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
        unsigned long sb_bindex, consumed_idx, consumed;
        struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
@@ -1615,7 +1648,7 @@ void lib_ring_buffer_put_subbuf(struct lttng_ust_lib_ring_buffer *buf,
  */
 static
 void lib_ring_buffer_print_subbuffer_errors(struct lttng_ust_lib_ring_buffer *buf,
-                                           struct channel *chan,
+                                           struct lttng_ust_lib_ring_buffer_channel *chan,
                                            unsigned long cons_offset,
                                            int cpu,
                                            struct lttng_ust_shm_handle *handle)
@@ -1650,9 +1683,8 @@ void lib_ring_buffer_print_subbuffer_errors(struct lttng_ust_lib_ring_buffer *bu
 
 static
 void lib_ring_buffer_print_buffer_errors(struct lttng_ust_lib_ring_buffer *buf,
-                                        struct channel *chan,
-                                        void *priv, int cpu,
-                                        struct lttng_ust_shm_handle *handle)
+                                        struct lttng_ust_lib_ring_buffer_channel *chan,
+                                        int cpu, struct lttng_ust_shm_handle *handle)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        unsigned long write_offset, cons_offset;
@@ -1680,12 +1712,11 @@ void lib_ring_buffer_print_buffer_errors(struct lttng_ust_lib_ring_buffer *buf,
 }
 
 static
-void lib_ring_buffer_print_errors(struct channel *chan,
+void lib_ring_buffer_print_errors(struct lttng_ust_lib_ring_buffer_channel *chan,
                                struct lttng_ust_lib_ring_buffer *buf, int cpu,
                                struct lttng_ust_shm_handle *handle)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
-       void *priv = channel_get_private(chan);
 
        if (!strcmp(chan->backend.name, "relay-metadata-mmap")) {
                DBG("ring buffer %s: %lu records written, "
@@ -1711,7 +1742,7 @@ void lib_ring_buffer_print_errors(struct channel *chan,
                                v_read(config, &buf->records_lost_wrap),
                                v_read(config, &buf->records_lost_big));
        }
-       lib_ring_buffer_print_buffer_errors(buf, chan, priv, cpu, handle);
+       lib_ring_buffer_print_buffer_errors(buf, chan, cpu, handle);
 }
 
 /*
@@ -1722,7 +1753,7 @@ void lib_ring_buffer_print_errors(struct channel *chan,
  */
 static
 void lib_ring_buffer_switch_old_start(struct lttng_ust_lib_ring_buffer *buf,
-                                     struct channel *chan,
+                                     struct lttng_ust_lib_ring_buffer_channel *chan,
                                      struct switch_offsets *offsets,
                                      uint64_t tsc,
                                      struct lttng_ust_shm_handle *handle)
@@ -1763,7 +1794,7 @@ void lib_ring_buffer_switch_old_start(struct lttng_ust_lib_ring_buffer *buf,
  */
 static
 void lib_ring_buffer_switch_old_end(struct lttng_ust_lib_ring_buffer *buf,
-                                   struct channel *chan,
+                                   struct lttng_ust_lib_ring_buffer_channel *chan,
                                    struct switch_offsets *offsets,
                                    uint64_t tsc,
                                    struct lttng_ust_shm_handle *handle)
@@ -1772,15 +1803,29 @@ void lib_ring_buffer_switch_old_end(struct lttng_ust_lib_ring_buffer *buf,
        unsigned long oldidx = subbuf_index(offsets->old - 1, chan);
        unsigned long commit_count, padding_size, data_size;
        struct commit_counters_hot *cc_hot;
+       uint64_t *ts_end;
 
        data_size = subbuf_offset(offsets->old - 1, chan) + 1;
        padding_size = chan->backend.subbuf_size - data_size;
        subbuffer_set_data_size(config, &buf->backend, oldidx, data_size,
                                handle);
 
+       ts_end = shmp_index(handle, buf->ts_end, oldidx);
+       if (!ts_end)
+               return;
        /*
-        * Order all writes to buffer before the commit count update that will
-        * determine that the subbuffer is full.
+        * This is the last space reservation in that sub-buffer before
+        * it gets delivered. This provides exclusive access to write to
+        * this sub-buffer's ts_end. There are also no concurrent
+        * readers of that ts_end because delivery of that sub-buffer is
+        * postponed until the commit counter is incremented for the
+        * current space reservation.
+        */
+       *ts_end = tsc;
+
+       /*
+        * Order all writes to buffer and store to ts_end before the commit
+        * count update that will determine that the subbuffer is full.
         */
        cmm_smp_wmb();
        cc_hot = shmp_index(handle, buf->commit_hot, oldidx);
@@ -1804,7 +1849,7 @@ void lib_ring_buffer_switch_old_end(struct lttng_ust_lib_ring_buffer *buf,
  */
 static
 void lib_ring_buffer_switch_new_start(struct lttng_ust_lib_ring_buffer *buf,
-                                     struct channel *chan,
+                                     struct lttng_ust_lib_ring_buffer_channel *chan,
                                      struct switch_offsets *offsets,
                                      uint64_t tsc,
                                      struct lttng_ust_shm_handle *handle)
@@ -1844,18 +1889,31 @@ void lib_ring_buffer_switch_new_start(struct lttng_ust_lib_ring_buffer *buf,
  */
 static
 void lib_ring_buffer_switch_new_end(struct lttng_ust_lib_ring_buffer *buf,
-                                   struct channel *chan,
+                                   struct lttng_ust_lib_ring_buffer_channel *chan,
                                    struct switch_offsets *offsets,
                                    uint64_t tsc,
                                    struct lttng_ust_shm_handle *handle)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        unsigned long endidx, data_size;
+       uint64_t *ts_end;
 
        endidx = subbuf_index(offsets->end - 1, chan);
        data_size = subbuf_offset(offsets->end - 1, chan) + 1;
        subbuffer_set_data_size(config, &buf->backend, endidx, data_size,
                                handle);
+       ts_end = shmp_index(handle, buf->ts_end, endidx);
+       if (!ts_end)
+               return;
+       /*
+        * This is the last space reservation in that sub-buffer before
+        * it gets delivered. This provides exclusive access to write to
+        * this sub-buffer's ts_end. There are also no concurrent
+        * readers of that ts_end because delivery of that sub-buffer is
+        * postponed until the commit counter is incremented for the
+        * current space reservation.
+        */
+       *ts_end = tsc;
 }
 
 /*
@@ -1866,7 +1924,7 @@ void lib_ring_buffer_switch_new_end(struct lttng_ust_lib_ring_buffer *buf,
 static
 int lib_ring_buffer_try_switch_slow(enum switch_mode mode,
                                    struct lttng_ust_lib_ring_buffer *buf,
-                                   struct channel *chan,
+                                   struct lttng_ust_lib_ring_buffer_channel *chan,
                                    struct switch_offsets *offsets,
                                    uint64_t *tsc,
                                    struct lttng_ust_shm_handle *handle)
@@ -1973,14 +2031,16 @@ int lib_ring_buffer_try_switch_slow(enum switch_mode mode,
  * Force a sub-buffer switch. This operation is completely reentrant : can be
  * called while tracing is active with absolutely no lock held.
  *
- * Note, however, that as a v_cmpxchg is used for some atomic
- * operations, this function must be called from the CPU which owns the buffer
- * for a ACTIVE flush.
+ * For RING_BUFFER_SYNC_PER_CPU ring buffers, as a v_cmpxchg is used for
+ * some atomic operations, this function must be called from the CPU
+ * which owns the buffer for a ACTIVE flush. However, for
+ * RING_BUFFER_SYNC_GLOBAL ring buffers, this function can be called
+ * from any CPU.
  */
 void lib_ring_buffer_switch_slow(struct lttng_ust_lib_ring_buffer *buf, enum switch_mode mode,
                                 struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan;
+       struct lttng_ust_lib_ring_buffer_channel *chan;
        const struct lttng_ust_lib_ring_buffer_config *config;
        struct switch_offsets offsets;
        unsigned long oldidx;
@@ -2059,14 +2119,16 @@ bool handle_blocking_retry(int *timeout_left_ms)
  */
 static
 int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
-                                    struct channel *chan,
+                                    struct lttng_ust_lib_ring_buffer_channel *chan,
                                     struct switch_offsets *offsets,
-                                    struct lttng_ust_lib_ring_buffer_ctx *ctx)
+                                    struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                                    void *client_ctx)
 {
+       struct lttng_ust_lib_ring_buffer_ctx_private *ctx_private = ctx->priv;
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
-       struct lttng_ust_shm_handle *handle = ctx->handle;
+       struct lttng_ust_shm_handle *handle = chan->handle;
        unsigned long reserve_commit_diff, offset_cmp;
-       int timeout_left_ms = lttng_ust_blocking_retry_timeout;
+       int timeout_left_ms = lttng_ust_ringbuffer_get_timeout(chan);
 
 retry:
        offsets->begin = offset_cmp = v_read(config, &buf->offset);
@@ -2076,23 +2138,23 @@ retry:
        offsets->switch_old_end = 0;
        offsets->pre_header_padding = 0;
 
-       ctx->tsc = config->cb.ring_buffer_clock_read(chan);
-       if ((int64_t) ctx->tsc == -EIO)
+       ctx_private->tsc = config->cb.ring_buffer_clock_read(chan);
+       if ((int64_t) ctx_private->tsc == -EIO)
                return -EIO;
 
-       if (last_tsc_overflow(config, buf, ctx->tsc))
-               ctx->rflags |= RING_BUFFER_RFLAG_FULL_TSC;
+       if (last_tsc_overflow(config, buf, ctx_private->tsc))
+               ctx_private->rflags |= RING_BUFFER_RFLAG_FULL_TSC;
 
-       if (caa_unlikely(subbuf_offset(offsets->begin, ctx->chan) == 0)) {
+       if (caa_unlikely(subbuf_offset(offsets->begin, chan) == 0)) {
                offsets->switch_new_start = 1;          /* For offsets->begin */
        } else {
                offsets->size = config->cb.record_header_size(config, chan,
                                                offsets->begin,
                                                &offsets->pre_header_padding,
-                                               ctx);
+                                               ctx, client_ctx);
                offsets->size +=
-                       lib_ring_buffer_align(offsets->begin + offsets->size,
-                                             ctx->largest_align)
+                       lttng_ust_lib_ring_buffer_align(offsets->begin + offsets->size,
+                                            ctx->largest_align)
                        + ctx->data_size;
                if (caa_unlikely(subbuf_offset(offsets->begin, chan) +
                             offsets->size > chan->backend.subbuf_size)) {
@@ -2195,9 +2257,9 @@ retry:
                        config->cb.record_header_size(config, chan,
                                                offsets->begin,
                                                &offsets->pre_header_padding,
-                                               ctx);
+                                               ctx, client_ctx);
                offsets->size +=
-                       lib_ring_buffer_align(offsets->begin + offsets->size,
+                       lttng_ust_lib_ring_buffer_align(offsets->begin + offsets->size,
                                              ctx->largest_align)
                        + ctx->data_size;
                if (caa_unlikely(subbuf_offset(offsets->begin, chan)
@@ -2249,28 +2311,30 @@ retry:
  * -EIO for other errors, else returns 0.
  * It will take care of sub-buffer switching.
  */
-int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
+int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+               void *client_ctx)
 {
-       struct channel *chan = ctx->chan;
-       struct lttng_ust_shm_handle *handle = ctx->handle;
+       struct lttng_ust_lib_ring_buffer_ctx_private *ctx_private = ctx->priv;
+       struct lttng_ust_lib_ring_buffer_channel *chan = ctx_private->chan;
+       struct lttng_ust_shm_handle *handle = chan->handle;
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        struct lttng_ust_lib_ring_buffer *buf;
        struct switch_offsets offsets;
        int ret;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
-               buf = shmp(handle, chan->backend.buf[ctx->cpu].shmp);
+               buf = shmp(handle, chan->backend.buf[ctx_private->reserve_cpu].shmp);
        else
                buf = shmp(handle, chan->backend.buf[0].shmp);
        if (!buf)
                return -EIO;
-       ctx->buf = buf;
+       ctx_private->buf = buf;
 
        offsets.size = 0;
 
        do {
                ret = lib_ring_buffer_try_reserve_slow(buf, chan, &offsets,
-                                                      ctx);
+                                                      ctx, client_ctx);
                if (caa_unlikely(ret))
                        return ret;
        } while (caa_unlikely(v_cmpxchg(config, &buf->offset, offsets.old,
@@ -2283,7 +2347,7 @@ int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
         * records, never the opposite (missing a full TSC record when it would
         * be needed).
         */
-       save_last_tsc(config, buf, ctx->tsc);
+       save_last_tsc(config, buf, ctx_private->tsc);
 
        /*
         * Push the reader if necessary
@@ -2304,21 +2368,21 @@ int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
                lib_ring_buffer_clear_noref(config, &buf->backend,
                                            subbuf_index(offsets.old - 1, chan),
                                            handle);
-               lib_ring_buffer_switch_old_end(buf, chan, &offsets, ctx->tsc, handle);
+               lib_ring_buffer_switch_old_end(buf, chan, &offsets, ctx_private->tsc, handle);
        }
 
        /*
         * Populate new subbuffer.
         */
        if (caa_unlikely(offsets.switch_new_start))
-               lib_ring_buffer_switch_new_start(buf, chan, &offsets, ctx->tsc, handle);
+               lib_ring_buffer_switch_new_start(buf, chan, &offsets, ctx_private->tsc, handle);
 
        if (caa_unlikely(offsets.switch_new_end))
-               lib_ring_buffer_switch_new_end(buf, chan, &offsets, ctx->tsc, handle);
+               lib_ring_buffer_switch_new_end(buf, chan, &offsets, ctx_private->tsc, handle);
 
-       ctx->slot_size = offsets.size;
-       ctx->pre_offset = offsets.begin;
-       ctx->buf_offset = offsets.begin + offsets.pre_header_padding;
+       ctx_private->slot_size = offsets.size;
+       ctx_private->pre_offset = offsets.begin;
+       ctx_private->buf_offset = offsets.begin + offsets.pre_header_padding;
        return 0;
 }
 
@@ -2369,7 +2433,7 @@ void deliver_count_events(const struct lttng_ust_lib_ring_buffer_config *config,
 
 void lib_ring_buffer_check_deliver_slow(const struct lttng_ust_lib_ring_buffer_config *config,
                                   struct lttng_ust_lib_ring_buffer *buf,
-                                  struct channel *chan,
+                                  struct lttng_ust_lib_ring_buffer_channel *chan,
                                   unsigned long offset,
                                   unsigned long commit_count,
                                   unsigned long idx,
@@ -2418,14 +2482,26 @@ void lib_ring_buffer_check_deliver_slow(const struct lttng_ust_lib_ring_buffer_c
        if (caa_likely(v_cmpxchg(config, &cc_cold->cc_sb,
                                 old_commit_count, old_commit_count + 1)
                   == old_commit_count)) {
+               uint64_t *ts_end;
+
                /*
                 * Start of exclusive subbuffer access. We are
                 * guaranteed to be the last writer in this subbuffer
                 * and any other writer trying to access this subbuffer
                 * in this state is required to drop records.
+                *
+                * We can read the ts_end for the current sub-buffer
+                * which has been saved by the very last space
+                * reservation for the current sub-buffer.
+                *
+                * Order increment of commit counter before reading ts_end.
                 */
+               cmm_smp_mb();
+               ts_end = shmp_index(handle, buf->ts_end, idx);
+               if (!ts_end)
+                       return;
                deliver_count_events(config, buf, idx, handle);
-               config->cb.buffer_end(buf, tsc, idx,
+               config->cb.buffer_end(buf, *ts_end, idx,
                                      lib_ring_buffer_get_data_size(config,
                                                                buf,
                                                                idx,
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